Pressure and temperature responsive pump control



F. E. ULLERY Dec, 12, 1%67 ii'LLISSUMfi AND TEMPERATURE RESPONSIVE PUMP CONTROL Filed Dec. 30, 1965 INVENTOR. Bed 5 U356 7 TTO PALE 7 .5,

United States Patent 3,357,635 PREfiSURE AND TEMPERATURE RESPONSIVE PUMP CONTROL Fred E. Ullery, Detroit, Mich, assignor to Ford Motor Company, Dear-horn, Mich, a corporation of Delaware Filed Dec. 30, 1965, Ser. No. 517,669 4 Claims. (Cl. 230-114) ABSTRACT OF THE DISCLOSURE An air turbine pump having a bladed rotor cooperating with a bladeless stator containing a pivotally movable seal or dam in the flow path to divert air flow under pressure to an outlet; the dam is a thermally responsive or pressure relief valve, is spring biased to a closed position, and is automatically movable to an air bypass position in response to predetermined air pressures and/ or temperature rises of the air.

This invention relates, in general, to a fluid pump control. More particularly, it relates to a compressor of the centrifugal type having means to bypass high pressure discharge fluid back to the pump inlet above a predetermined pump discharge pressure or fluid temperature.

Present day motor vehicles are being equipped with engine secondary air injection manifolds or similar devices to supply additional air to the engine exhaust system so that any unburned hydrocarbons and other harmful elements that exist in the exhaust gases can be converted to less harmful forms before entering the atmosphere. This secondary source of air generally is supplied independently of the primary air intake system, and by an air compressor that usually is mounted on the engine as an accessory.

In substantially all cases, the air pump is rotated continuously, and therefore consumes a considerable amount of useful engine output horsepower at high engine speeds when the pump output provides more air than is needed. Also, at sustained higher engine speeds, the pump tends to run hot, which can decrease the life of the pump. It is a primary purpose of the invention, therefore, to provide a control for an air pump that is effective either above a predetermined pump pressure or fluid temperature, or both, to bypass air from the high pressure outlet side of the pump back to the low pressure inlet side, to reduce the load on the pump and the horsepower required to drive it, and reduce the fluid temperature. This results in a saving of useful horsepower and a greater engine operating efficiency, and increases the life of the pump.

One of the objects of the invention, therefore, is to provide a fluid pump control that at times permits a bypass of fluid from the high pressure to the low pressure side of the pump.

Another object of the invention is to provide a centrifugal air pump having cooperating rotor and stator members, the stator member having a fluid inlet and outlet and a control normally blocking communication therebetween in one direction of flow, the control being operable at times to permit a flow of air from the high to the low pressure side of the pump.

A further object of the invention is to provide an air compressor or pump with a fluid bypass that is operable at higher pump pressures or temperatures to reduce the pump temperature and the load on the pump, and therefore the horsepower required to drive the pump.

A still further object of the invention is to provide a centrifugal air pump with an air bypass control consisting of a gate pivotal into and out of the stator chamber fluid flow path to control communication betwen the high and low pressure sides of the pump; the gate being Patented Dec. 12, 1967 spring biased into a bypass flow preventing position and movable in response to either a high fluid discharge pressure or a predetermined rise in the temperature of the fluid to a position permitting a bypass of air.

Another object of the invention is to provide an air pump bypass control of the type described that limits the pump pressure developed according to functional needs, and minimizes the developed air pressure during sustained high speeds, to avoid in-expedient power absorption by the pump, and to restrict the operating temperature of the pump in furtherance of endurance.

Other objects, features and advantages of the invention will become apparent upon reference to the succeeding, detailed description thereof, and to the drawings illustrating the preferred embodiments thereof; wherein:

FIGURE 1 shows a cross-sectional view of one embodiment of a pump and fluid bypass control incorporating the invention;

FIGURE 2 is a cross-sectional view taken on a plane indicated by and viewed in the direction of arrows 2-2 of FIGURE 1;

FIGURE 3 is a rear-elevationa-l view of the pump shown in FIGURE 1;

FIGURE 4 is a perspective view of the bypass control of FIGURE 1;

FIGURE 5 is a view similar to FIGURE 4 showing another embodiment of the invention; and,

FIGURE 6 shows a modification of the FIGURE 2 showing.

FIGURE 1 shows an air pump or compressor 10 of the centrifugal type. It includes a semi-toroidal driving shell or casing 12 that is welded or otherwise secured to a V-type drive pulley 14. The pulley is driven at, say three times engine crankshaft speed, for example, by a suitable belt drive type connection (not shown). The pulley is fixed on a sleeve 16 that is rotatably mounted on a stationary shaft 18 by a pair of spaced annular ball bearing units 20 and 22.

Shell 12 supports a number of circumferentially spaced impeller or pump blades 24 to define a rotor member 26. Blades 24 are substantially dish-shaped in cross section, and cooperate with and face a semi-toroidal shaped cavity 28 defined by a stationary casing 30. The casing constitutes a stator member 31, and is hollow and bladeless. The stator has a hub 32 fixedly secured to shaft 18, the shaft being bolted or otherwise secured to a stationary engine mounting flange-3'3.

The stator has an air inlet opening 34 (FIGURE 3) and a fluid discharge outlet 36 located on opposite circumferential sides of an air bypass control unit 38. As will be described later, the control unit normally prevents direct communication between the air inlet and outlet as blades 24 (FIGURE 1) pass over the face seal portion 40 in a known manner.

In general operation, as thus far described, rotation of rotor 26 by pulley 14 in a counterclockwise direction in a left to right axial view of FIGURE 1 causes air to be drawn in through inlet 34 into the spaces (not shown) between blades 24. The air is then centrifuged outwardly and forwardly into the stator cavity 28, where it is redirected back into the rotor blade cavities to impart additional energy to the blades. This continuing cycling imparts a helical spiral motion to the air, causing it to flow around the toroidal circuit until it reaches the bypass control unit 38, at which point it is diverted into the outlet '36 under pressure.

Turning to the invention, the bypass control unit 38 consists, in general, of a gate or valve plate 46 that is pivotally mounted on the stator casing, and either is spring pivoted into the fluid flow path to block the pas- 3 sage of air from outlet 36 to inlet 34, as seen in FIGURE 2, or can be pivoted towards the dotted line position 48 out of the circuit to a fluid flow bypass position in response to a high air discharge pressure acting against it or a rise in temperature of the air above a selected value, or both.

More specifically, stator casing 30- is enlarged at 50 (FIGURE 2) and suitably bored to rotatably receive a vertical axis pivot pin 52. Gate member 46 is secured to the pin, and is swingable from the full line position shown in FIGURE 2 to the dotted line position 43. In the full line position, the gate cooperates with a circumferentially narrow bridge member 54 to completely block flow from outlet 36 to inlet 34 in the direction of arrow 56. The inner face 40 of the bridge acts as a seal surface with respect to rotor blades 24 to prevent circumferential leakage of fluid at this point as the blades rotate past bridge 54.

As seen in FIGURE 1,.pivot shaft 52 extends upwardly into the housing 58 of a control unit 60. This unit includes a base plate 61 to which housing 58 is clamped, the base plate being screwed to stator casing 30 and acting as a locator and bearing member for pivot shaft 2..Rotatably mounted on pin 52 is a sleeve 62 having spaced arcuate slots 64 at one end, and an axial slot 66 (see FIGURE 4) in the opposite enlarged end.

Slot 66 receives the inner end 67 of a coil type thermostatic element 68, the outer end of which projects through a slot 70 in housing 58 so as to be fixed thereto. The base plate 61 is provided with suitable air bleed holes 69 that will subject the thermostatic element to the temperature of the fluid near the outlet 36. A suitable atmospheric vent (not shown) would also be provided to induce flow into the housing interior. An air bleed hole connected to the inlet side of the pump could also be provided, if desired.

Sleeve slots 64 slidably receive two pins 72 and 74 projecting from shaft 52. A torsion spring 76 is coiled around sleeve 62, and is fixed at one end in an anchor hole 78 in sleeve 62 and at its opposite end bears against pin 72. The spring 76 is chosen to be relatively soft in comparison to the stiffer resistance to movement of the thermostatic element 68.

Since sleeve 62 is in effect grounded to the stator casing through the stifi resistance of thermostatic element 68 a chosen preload on torsion spring 76 will position the pins 72 and 74 at some location relative to the ends of the sleeve slots 64 suflicient to bias the valve plate or gate 46 against the bridge member 54 (FIGURE 2).

Assume, for example, that for the closed position of the gate 46, the pin 72 is located near the midpoint of slot 64 shown in FIGURE 4. When the pump discharge pressure (acting in the direction of arrow 79) increases to a value sufiicient to overcome the preload on spring 76, gate 46 and shaft 52 will rotate or pivot towards the dotted line position 48 (FIGURE 2) and permit bypass of a predetermined volume of air from the pump outlet 36 back to the inlet 38. The pressure and temperature will then of course be reduced, and will reduce the load on the pump and the engine horsepower needed to drive it.

If during the above operation the pump should heat up to a value beyond that desired, the high temperature of the fluid in housing 58 will cause the thermostatic element to wind up and rotate sleeve 62 in a direction moving the end 80 of slot 64 towards pin 72. When the sleeve slot end engages pin 72, it will rotate it and shaft 52 and gate 46 to a further open or bypass position. This will permit a greater flow of air and reduction in the pump pressure and temperature.

It will be clear, of course, that the thermostatic element can operate independently of spring 76; that is, if the pump temperature should rise to a high value at a time when the discharge pressure is lower than that necessary to overcome the preload of spring 76, sleeve 62 will rotate to engage pin 72 and direct-1y rotate gate 46 to an air bypass position.

FIGURE 4 shows a construction where the spring :76 and thermostatic element 68 essentially are in a series structural arrangement. That is, the air pressure acting on gate 46 is opposed by the force of spring 76, which is grounded to the stator casing through the sleeve 62 and thermostatic unit 68. FIGURE 5 illustrates a construction in which they are arranged in parallel.

In FIGURE 5, collar 62' is fixed on shaft 52' and has an abutment surface 82 adapted to cooperate with the inner ,end of the thermostatic element 68. Spring 76' is anchored to the collar 62, and reacts against a portion 84 of the stator housing at its opposite end.

The air pressure will rotate collar 62 against the force of spring 76'. Also, the thermostatic unit can independently rotate the collar 62 after abutting the surface 82 as the coil element 68' winds up.

While the invention has been illustrated in its preferred embodiments in the figures, it will be clear to those skilled in the arts to which the invention pertains that many changes and modifications may be made thereto without departing from the scope of the invention. For example, as shown in FIGURE 6, the gate 46 could be pivotally mounted on the bridge member 54" instead of as shown in FIGURE 2.

I claim:

1. A centrifugal pump having a bladed rotor member, a hollow stator member cooperating therewith to define an annular fluid flow chamber therebetween, said stator member having a fluid inlet and outlet to said chamber, a source of fluid connected to said inlet, and fluid bypass control means in said stator chamber movable between positions blocking or permitting flow between said inlet and outlet in one direction, and means for controlling the movement of said bypass control means, said last mentioned means including spring means biasing said control means to a fluid blocking position, said control means being acted upon by the fluid under pressure at said outlet and moved above a predetermined fluid pressure towards the bypass fluid flow-permitting position, and temperature responsive means movable in response to a rise in temperature of said fluid to decrease the force of said spring means and permit a pressure lower than said predetermined fluid pressure to move said control means to its bypass flow-permitting position.

2. A pump as in claim 1, said last-mentioned means including spring means biasing said control means to a fluid blocking position, said control means being acted upon by the fluid under pressure at said outlet and moved above a predetermined fluid pressure towards the bypass fluid flow permitting position, and temperature responsive means operable above a predetermined temperature of said fluid to move said control means against the force of said spring means to its bypass flow permitting position.

3. A pump as in claim 1, said last'mentioned means including means biasing said control means to a fluid blocking position, said bypass control means being acted upon by said fluid at said outlet and moved to a bypass flow permitting position above a predetermined pressure of the fluid thereagainst, said last-mentioned means including spring means biasing said control means to a fluid blocking position, said control means being acted upon by the fluid under pressure at said outlet and moved above a predetermined fluid pressure towards the bypass fluid flow permitting position, and temperature responsive means movablein response to a rise in temperature of said fluid to decrease the force of said spring means and permit a pressure lower than said predetermined fluid pressure to move said control means to its bypass flowpermitting position.

4. A pump as in claim 1, said last-mentioned means including means biasing said control means to a fluid blocking position, said bypass control means being acted upon by said fluid at said outlet and moved to a bypass flow permitting position above a predetermined pressure of the fluid thereagainst, said last-mentioned means including spring means biasing said control means to a fluid blocking position, said control means being acted upon by the fluid under pressure at said outlet and moved above a predetermined fluid pressure towards the bypass fluid flow-permitting position, and temperature responsive means operable above a predetermined temperature of said fluid to move said control means against the force of said spring means to its bypass-flow-permitting position.

References Cited UNITED STATES PATENTS 2,385,096 9/1945 McCollum 230-114 2,455,552 12/1948 Bower 103-97 3,257,955 6/1966 Worst 103-96 DONLEY J. STOCKING, Primary Eaminer. HENRY F. RADUAZO, Examiner. 

1. A CENTRIFUGAL PUMP HAVING A BLADED ROTOR MEMBER, A HOLLOW STATOR MEMBER COOPERATING THEREWITH TO DEFINE AN ANNULAR FLUID FLOW CHAMBER THEREBETWEEN, SAID STATOR MEMBER HAVING A FLUID INLET AND OUTLET TO SAID CHAMBER, A SOURCE OF FLUID CONNECTED TO SAID INLET, AND FLUID BYPASS CONTROL MEANS IN SAID STATOR CHAMBER MOVABLE BETWEEN POSITIONS BLOCKING OR PREMITTING FLOW BETWEEN SAID INLET AND OUTLET IN ONE DIRECTION, AND MEANS FOR CONTROLLING THE MOVEMENT OF SAID BYPASS CONTROL MEANS, SAID LASTMENTIONED MEANS INCLUDING SPRING MEANS BIASING SAID CONTROL MEANS TO A FLUID BLOCKING POSITION, SAID CONTROL MEANS BEING ACTED UPON BY THE FLUID UNDER PRESSURE AT SAID OUTLET AND MOVED ABOVE A PREDETERMINED FLUID PRESSURE TOWARDS THE BYPASS FLUID FLOW-PERMITTING POSITION, AND TEMPERATURE RESPONSIVE MEANS MOVABLE IN RESPONSE TO A RISE IN TEMPERATURE OF SAID FLUID TO DECREASE THE FORCE OF SAID SPRING MEANS AND PERMIT A PRESSURE LOWER THAN SAID PREDETERMINED FLUID PRESSURE TO MOVE SAID CONTROL MEANS TO ITS BYPASS FLOW-PERMITTING POSITION. 